How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

In this tutorial, I will introduce you to the traditional process of paper stretching. There are a lot of tutorials and videos on the subject, but I want to take you through my many, many mistakes—ones that you can avoid—as well as teaching you how to stretch your watercolour paper.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Why Stretch Paper?

If you don’t stretch paper, it will buckle—the thinner the paper, the worse the buckling, and the greater the chances of it tearing. This will lead to unsightly undulations in your work and puddling and pooling of your paint.

Many artists avoid stretching paper altogether, while some use staples to secure their paper. I find this destroys my board after only a short time, and I struggle to remove the staples.

I am very heavy-handed with my watercolours and gouache. Very. I need paper that will take all the abuse I can throw at it, and I have found a simple stretching process that still holds the paper flat once my paintings have dried. It works for me 95% of the time, and if on that rare occasion my paper has dried buckled, I simply cut out the paper and do it again using the same sheet. It is a wee bit smaller because of the tape, but it’s not completely wasted.

Below is an example of 100gsm with a very light touch of watered-down paint.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

I used to buy pre-stretched blocks of paper but found that the gum around the edges would tear over time. The stretch wasn’t strong enough either, and the more I removed my finished paintings from the block, the weaker the stretch became. I eventually found I couldn’t use the last eight or so sheets unless I stretched them myself anyway. And these blocks are expensive.

What You Will Need

1. Board for Stretching Your Paper Upon

I only use one type of board—conti. It is the white furniture panel that cupboards and kitchen units are made out of and can be easily found in most DIY shops. It has woodchips in the middle which are sandwiched between melamine. It is durable, can put up with all the water I have been known to throw at it, is easy to clean after use (leaving it smooth), can be used over and over again, and is inexpensive for a lot of board.

The thickness I use is 1.5cm, and the DIY shop cuts it down to the sizes I want. I tend to have five paintings on the go at the same time (so I can keep working as
other paintings dry), and I got my five boards from one sheet of conti. Its downside is that it can be heavy, but once it is cut down to the sizes I prefer to work on, it is very manageable.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

My Mistake: I used to use normal wood, which was porous, and my tape wouldn’t stick to it 75% of the time. If it did stick, I either couldn’t get the tape back off once the painting was finished so I could reuse the wood, or the tape removed chunks and splinters, leaving a ragged surface. MDF had the same problems and expanded when it was too wet.

My Mistake: I did some research online and sealed the wood and MDF but found that my paintings would stick to this extra coat and tore when I tried to remove them; or the sealant would lift off the wood with the tape as it dried, which defeated the purpose.

2. Paper

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

I tend to use 220gsm and 300gsm paper. They cope well with the quantities of liquids and punishment I mete out, but only once stretched. You can get all sorts of textured or smooth papers, and it is really up to you what you prefer, but stretching them is more important the lighter they are. The standard ones are 190gsm, 300gsm, 356gsm, and 638gsm (this is coming into the realms
of card and can be expensive).

Try to choose an acid-free paper as this will help prevent the deterioration of your colours. The texture is up to you, but I would recommend a NOT (also known as cold pressed) paper. The surface is not too rough and not too smooth (that’s not why it’s called NOT, which refers to
the way the paper has been made—not hot pressed).

3. Gummed Tape and Other Material

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Gummed Tape

Gummed tape is basically a strip of brown paper with thin dry glue on one side (the shiny side). This can be bought from all good art shops and online. I use 5cm wide tape. In the past, I have used 2.5cm, but it was too narrow and didn’t keep my paper stretched.

Sponge

Any flat sponge will do that can be easily wrung out. Mine is a kitchen one that is small enough to be comfortably held in my hand and has a flat, smooth surface.

Scissors

Scissors are optional. I always have them at the ready, but prefer to tear the gummed tape to size (it rips very easily).

Make Some Decisions

Where Are You Going to Work?

You will need somewhere that you don’t mind getting wet, with enough space to lay your conti board flat. I use my bathroom.

What Is Going to Contain Your Water?

Choose something that is big enough to hold your preferred size of paper flat; a large basin, sink, bath, or shower tray (with its drain blocked with a tennis ball). I use my bath.

Where Will You Be Able to Comfortably Work on Your Board?

I rest mine flat on the toilet; it’s far from glamorous, but it works. Use a table, put it on the floor, or securely place it on a sink.

Where Can You Lay Your Gummed Tape?

I do this on the edge of my sink because it is flat, but you can use another conti board or the edge of your bath.

Where Will You Leave Your Stretching Paper to Dry?

This is the slow bit, so find somewhere you can leave your board (or boards) flat overnight, undisturbed.

Stretching Your Paper

Measure out strips of your gummed tape along each side of your dry paper, tearing or cutting them so that each width is about 6cm wider than each side of your paper. I measure by eye, just unrolling the tape and holding it against the paper as I go. I split out the lengths, putting the shorter and longer lengths in separate piles.

My Mistake: My hands were slightly damp when I measured out the gummed paper. They stuck to themselves, to me, and to the surface I placed them on. Make sure your hands and the surface you are placing them on are dry.

My Mistake: I didn’t have long enough strips, and they didn’t have enough tape on either end to stick to the conti board.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Fill your bath/basin/sink with around 5–10cm deep of cold water and place your paper in it, pushing it down gently with spread fingers so that all of it is covered by the water. It will still float on the surface. I leave 300gsm paper for 15 minutes and 220gsm for 10 minutes. Anything thinner than that, I leave for 5 minutes or less.

My Mistake: I didn’t leave the paper for long enough, and the paper didn’t soak all the way through. It buckled when it was dry, tearing at the tape I had placed round it. Useless. But this paper can be reused. Just cut off the tape, and soak it again properly.

My Mistake: I left the paper for too long, and it tore.

Have your sponge at the ready.

After the allotted time, lift your paper out of its water using both your hands at opposite corners. Give it a gentle wiggle to get rid of excess water and lay it flat on your conti board from the bottom of the paper to your hands. If it’s not straight, lift it up again by the same two corners and lay it gently down again. Don’t try sliding it about—you won’t be able to.

The paper may have bubbles in it or not want to lie completely flat, but that is OK. Just gently wipe it down with your sponge (squeeze it out every so often), taking care to move from the middle out. Don’t rub back and forth; just sweep in one direction. If the bubbles are still there, again, don’t worry—these will disappear when it stretches.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

My Mistake: I rubbed too hard and tore the paper or rubbed off the top layer of the paper. Keep it light handed.

On a flat dampened surface, lay your first strip of tape gummed or shiny side up. This will keep it flat—it always wants to roll back up.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Hold one end of it with one finger and with a damp sponge stroke from your finger to the opposite end across the glue—once only. It will now lie flat. Have a look at the tape, and if there are any bits that are not wet, touch them up gently (including the bit where your
finger was).

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

My Mistake: I dipped the entire tape into water. All the glue washed off.

My Mistake: I rubbed the sponge across the tape too often and rubbed all the glue off.

My Mistake: I wasn’t gentle enough when stroking my sponge across the tape, making it too wet, and it stuck to itself.

My Mistake: I didn’t maintain dry hands, and the tape stuck to me.

Using two hands, place your tape on the wet paper, overlapping the paper and the conti board—2cm of tape should be on your paper—and gently smooth it out with your sponge. If it sits at an angle, slide it into place, but try not to move it about too much as you will lose glue.

Keep squeezing your sponge out as often as possible.

My Mistake: I used one hand when lifting it, and the tape stuck to itself.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Repeat this process with all four sides.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Using your sponge, press the tape into the edges of the paper, but don’t fiddle with it too much. Again, squeeze out excess water from your sponge as you go.

You will find that as it dries, the paper will buckle, but it will flatten out as time goes on.

Leave your paper to dry overnight or until it is no longer cold to the touch, and as tempting as it is, don’t use a hairdryer on it. The paper and tape need to dry at the same pace, slowly.

Using Your Stretched Paper

Once your paper is dry, it is ready to use. However, I have sometimes found that the tape has torn. But if the paper is flat, I’ve still been able to use it without any consequences, as you can see below.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

The paper did buckle a bit when it was wet, but dried flat every time.

Once you have finished your painting, use a sharp knife and ruler to cut it out. It doesn’t matter if you cut into the conti board as the scores don’t seem to affect the next paper I stretch. Just try to avoid it if you can, as you want the board to last a long time.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

You can also see in the image above how the tape has torn along the edge of the paper. This didn’t affect the paper while I worked on it—and this painting had gesso, sand medium, glues, and oriental papers stuck to it as well as watercolour and gouache paints.

Below is an example of a painting in progress; you can just see where the paint is pooling (the blue puddle). This is where the paper is buckling because I have laid so much down on it. Again, the painting dried flat.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Preparing a Used Board

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Tear off the remaining tape and paper after removing your painting (you can see where I scored the board with my knife,
above) and using a Stanley knife blade, scrape off anything else that still remains (below). Use a damp sponge to wipe away excess paper and paint, effectively cleaning the conti, ready for your next stretching session.

How to Stretch Paper for Watercolour and Gouache and Avoid My Mistakes!

Conclusion

Stretching paper takes patience. The actual activity time is fairly short; it’s the drying time that takes a while. I have found it to be very worthwhile, and given that artists have been doing it for centuries, I find it very warming that I am part of that old, old tradition.

Just avoid my mistakes and you’ll be fine.